JP7344026B2 - Scintillator plate, image acquisition device, and scintillator plate manufacturing method - Google Patents

Description

One aspect of the present invention relates to a scintillator plate, an image acquisition device, and a method for manufacturing a scintillator plate.

Patent Document 1 describes a scintillator plate that converts incident radiation into an optical image in a wavelength range that can be detected by an image sensor. The scintillator plate includes a base material and a scintillator provided on the base material.

Japanese Patent Application Publication No. 2009-103676

Here, for example, when providing a relatively thin scintillator (for example, thinner than 20 μm), if the surface of the base material has unevenness, the surface of the scintillator will also be affected by the unevenness, and the converted optical image will be affected by the unevenness. The problem is that the resolution is low.

One aspect of the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a scintillator plate, an image acquisition device, and a scintillator plate manufacturing method that can improve image quality.

A scintillator plate according to one aspect of the present invention includes a base material that transmits X-rays and a scintillator provided on one surface of the base material, and one surface of the base material is mirror-finished.

As described above, in the scintillator plate according to one aspect of the present invention, one surface of the base material on which the scintillator is provided is mirror-finished. By mirror-finishing one side of the base material to make it smooth, the surface of the scintillator provided on one side of the base material can be smoothed, and the resolution of the optical image after conversion by the scintillator can be improved. can. As described above, according to the scintillator plate according to one aspect of the present invention, image quality can be improved.

The surface roughness Ra of one side of the base material may be 0.1 or less. Thereby, one side of the base material can be appropriately smoothed, and the quality of the image can be improved.

The thickness of the scintillator may be 20 μm or less. For example, when acquiring an image using X-rays of low energy (for example, 30 KeV or less), the image can be appropriately acquired by reducing the thickness of the scintillator to about 20 μm or less. When the thickness of the scintillator becomes thinner, the surface of the scintillator becomes more susceptible to the effects of unevenness on one side of the base material.However, as mentioned above, one side of the base material is mirror-finished, so that the scintillator thickness can be reduced. The quality of the image can be ensured even when the image is thin.

The scintillator may be formed of a powdered scintillator. Thereby, the scintillator can be appropriately provided even when the thickness of the scintillator is to be reduced, for example.

The base material may include beryllium. Thereby, the scintillator can be held while suitably transmitting X-rays.

An image acquisition device according to one aspect of the present invention includes the scintillator plate described above, an imaging section optically coupled to a surface side of the scintillator plate on which the scintillator is provided, and a fluorescence generated in the scintillator plate directed toward the imaging section. A reflective part that reflects the light. According to the image acquisition device having the scintillator plate described above, the quality of captured images can be improved.

A method for manufacturing a scintillator plate according to one aspect of the present invention includes the steps of mirror-finishing one surface of a base material that transmits X-rays, and providing a scintillator on one surface of the base material after the mirror-finishing step. Be prepared. According to such a manufacturing method, it is possible to manufacture a scintillator plate in which a scintillator is appropriately provided on the mirror-finished surface of the base material. That is, a scintillator plate that can improve image quality can be appropriately manufactured.

In the mirror finishing step, mirror finishing may be performed so that the surface roughness of one side of the base material is 0.1 or less.

In the step of providing the scintillator, the scintillator may be provided so that the thickness of the scintillator is 20 μm or less.

In the step of providing a scintillator, a powdered scintillator may be deposited on one side of the substrate.

According to one aspect of the present invention, image quality can be improved.

FIG. 1 is a schematic configuration diagram of a scintillator plate according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a method for manufacturing the scintillator plate shown in FIG. 1. FIG. 2 is a schematic configuration diagram of an X-ray image acquisition device using the scintillator plate shown in FIG. 1. FIG. FIG. 3 is a schematic configuration diagram of a scintillator plate according to a comparative example. It is a figure which shows the X-ray image at the time of using the scintillator plate based on a comparative example. It is a figure which shows the X-ray image at the time of using the scintillator plate based on a comparative example. FIG. 3 is a diagram showing an X-ray image when using the scintillator plate according to the present embodiment.

Hereinafter, one embodiment of the scintillator plate according to the present invention will be described in detail with reference to the drawings. In addition, in the description of the drawings, the same or corresponding parts are given the same reference numerals, and redundant description will be omitted. Furthermore, each drawing is created for the purpose of explanation, and is drawn so as to particularly emphasize the target portion of the explanation. Therefore, the dimensional ratio of each part in the drawings does not necessarily match the actual one.

FIG. 1 is a schematic diagram of a scintillator plate according to an embodiment of the present invention. The scintillator plate 1 is a member that converts radiation such as X-rays transmitted through an object into scintillation light. The present embodiment will be described assuming that the radiation irradiated to the scintillator plate 1 is X-rays. The scintillator plate 1 includes a base material 2 and a scintillator 3.

The base material 2 is a flat member that transmits X-rays. The base material 2 supports a scintillator 3 provided on one surface 2a thereof. The thickness of the base material 2 is approximately several tens of μm to 5 mm, for example, approximately 0.5 mm. The base material 2 has the property of transmitting X-rays and blocking scintillation light generated by the scintillator 3. As the base material 2, for example, a beryllium plate is used. That is, the base material 2 is configured to include beryllium. As the base material 2, for example, a carbon plate, a glass plate member such as FOP (Fiber Optic Plate), or an aluminum plate may be used, or a metal plate member such as titanium, gold, silver, iron, etc. may be used. Alternatively, a resin plate member such as a plastic plate may be used.

One surface 2a of the base material 2 that supports the scintillator 3 is mirror-finished. That is, one surface 2a of the base material 2 is ground before the scintillator 3 is provided so that the irregularities on the surface are made smooth (smooth enough to function as a mirror that reflects objects). The surface roughness Ra of one surface 2a of the base material 2 is, for example, 0.1 or less.

The scintillator 3 is provided on one surface 2a of the base material 2. The scintillator 3 is a wavelength conversion member (phosphor) that generates scintillation light (fluorescence) in response to incident X-rays. The material and thickness of the scintillator 3 are selected depending on the energy band of the X-rays to be detected. Examples of materials for the scintillator 3 include Gd2O2S:Tb, Gd2O2S:Pr, CsI:Tl, CdWO4, CaWO4, Gd2SiO5:Ce, Lu0.4Gd1.6SiO5, Bi4Ge3O12, Lu2SiO5:Ce, Y2SiO5, YAlO3:Ce, Y2O2S:Tb, YTaO4:Tm etc. are used. The thickness of the scintillator 3 is approximately several μm to several tens of μm, for example, 20 μm or less, or 10 μm or less. In this embodiment, the scintillator 3 is in powder form and is applied to one surface 2a of the base material 2.

As shown in FIG. 1, the base material 2 is supported by a holder 101. Further, as a configuration for evaluating the image quality (resolution) of an image acquired using the scintillator plate 1, a resolving power chart is provided on the X-ray irradiation side as instructed by the holder 101.

Next, the manufacturing process (manufacturing method) of the scintillator plate 1 described above will be explained with reference to FIG. 2. FIG. 2 is a diagram illustrating a manufacturing process (manufacturing method) of the scintillator plate 1 shown in FIG. 1.

In the manufacturing process of the scintillator plate 1, first, as shown in FIG. 2(a), a base material 2 (a base material that transmits X-rays) made of a beryllium plate or the like is prepared. The base material 2 shown in FIG. 2(a) is a base material before being subjected to mirror finishing.

Subsequently, as shown in FIG. 2(b), one surface 2a of the base material 2 is mirror-finished (step of mirror-finishing). In the mirror polishing step, mirror polishing is performed so that the surface roughness of one surface 2a of the base material 2 is 0.1 or less. The mirror finishing of the one surface 2a of the base material 2 may be performed by any method as long as it can reduce the surface roughness Ra of the one surface 2a of the base material 2 to approximately 0.1 or less, for example. This is done by belt polishing, paper polishing, buffing, etc. Note that the other surface 2b of the base material 2 that faces the one surface 2a of the base material 2 may or may not be mirror-finished.

Subsequently, as shown in FIG. 2(c), a scintillator 3 is applied to one surface 2a of the mirror-finished base material 2 (step of providing a scintillator). In the step of providing the scintillator, the scintillator is provided so that the thickness of the scintillator 3 is, for example, 20 μm or less. Further, in the step of providing the scintillator, for example, a powdered scintillator is deposited on one surface 2a of the base material 2. The above is the manufacturing process (manufacturing method) of the scintillator plate 1.

Next, the configuration of an X-ray image acquisition apparatus that uses the scintillator plate 1 of this embodiment to acquire X-ray images of objects such as electronic components such as semiconductor devices and foodstuffs will be described with reference to FIG. do. FIG. 3 is a schematic configuration diagram of an X-ray image acquisition apparatus 10 using the scintillator plate 1 shown in FIG. 1. An X-ray image acquisition device (indirect X-ray detector) as shown in FIG. 3 is used, for example, in various experiments at a synchrotron radiation facility.

As shown in FIG. 3, the X-ray image acquisition device 10 includes a scintillator plate 1, a reflection mirror 20 (reflection section), a relay lens 30, a lens attachment 40, and a camera 50 (imaging section). ing.

As described above, the scintillator plate 1 includes a base material 2 that transmits X-rays and a scintillator 3 that generates scintillation light in response to incident X-rays. In the scintillator plate 1, X-rays emitted from an X-ray source (not shown) that emits X-rays such as white X-rays and transmitted through a target object (not shown) enter a base material 2, and are transmitted through the base material 2. The X-rays are incident on the scintillator 3, and the scintillator 3 generates scintillation light in response to the incidence of the X-rays. The scintillation light emitted by the scintillator 3 reaches the reflection mirror 20.

The reflecting mirror 20 is a mirror that reflects scintillation light (fluorescence) generated in the scintillator plate 1 toward the camera 50. The scintillation light reflected by the reflecting mirror 20 reaches the relay lens 30. The relay lens 30 is provided after the reflecting mirror 20 and is a lens for forming an image of scintillation light. The scintillation light that has passed through the relay lens 30 reaches the lens attachment 40.

The lens attachment 40 is attached to the camera 50 and includes a condensing lens. The camera 50 is an imaging unit optically coupled to the surface of the scintillator plate 1 on which the scintillator 3 is provided. The camera 50 images the scintillation light. The camera 50 captures an image of scintillation light by detecting an image formed through the relay lens 30 and the lens attachment 40. The camera 50 outputs a scintillation light image, which is the imaging result, to a control device (not shown). The camera 50 is, for example, an area image sensor such as a CCD or CMOS. Further, the camera 50 may be configured by a line sensor or a TDI (Time Delay Integration) sensor. The scintillation light image acquired by the camera 50 may be displayed on a display device (not shown) by a control device (not shown).

Next, the effects of this embodiment will be explained while comparing with a comparative example.

FIG. 4 is a schematic configuration diagram of a scintillator plate according to a comparative example. FIG. 5 is a diagram showing an X-ray image obtained when using a scintillator plate according to a comparative example. The scintillator plate shown in FIG. 4 includes a base material 2, a scintillator 503, and a glass member 500. The glass member 500 is, for example, synthetic quartz glass. In the configuration shown in FIG. 4, a scintillator 503 is provided on the glass member 500. In such a configuration, X-rays transmitted through the base material 2 enter the scintillator 503, the scintillator 3 generates scintillation light in response to the incidence of the X-rays, and the scintillation light passes through the glass member 500 and is detected. Detected by an optical system (camera, etc.). Here, the detection optical system observes the scintillation light through the glass member 500. Observation of scintillation light through the glass member 500 causes a problem in that the optical properties deteriorate and the image quality (resolution) of the obtained X-ray image becomes low (see FIG. 5).

Therefore, the present inventors studied a scintillator plate that excludes the glass member 500 as described above. The present inventors suppressed the deterioration of optical properties and improved the image quality (resolution) of X-ray images by providing (coating) the scintillator 3 directly on the base material 2 without using the glass member 500 as described above. I have found that things can be improved.

However, in the process of the above study, it became clear that simply applying the scintillator 3 to the base material 2 does not sufficiently improve the image quality of X-ray images. The present inventors considered that the roughness of the surface of the base material 2 to which the scintillator 3 is applied (surface irregularities) affects the quality of the acquired X-ray image. In other words, the present inventors found that if the surface of the base material 2 on which the scintillator 3 is applied is uneven, the surface of the scintillator 3 will also be affected by the unevenness, and the resolution of the converted optical image will be low. I thought it would be. Based on such studies, the present inventors have invented a scintillator plate 1 in which the surface of the base material 2 on which the scintillator 3 is applied is mirror-finished.

The scintillator plate 1 according to this embodiment includes a base material 2 that transmits X-rays, and a scintillator 3 provided on one surface 2a of the base material 2, and one surface 2a of the base material 2 is mirror-finished.

In this manner, in the scintillator plate 1 according to the present embodiment, one surface 2a of the base material 2 on which the scintillator 3 is provided is mirror-finished. Since one surface 2a of the base material 2 is mirror-finished and smooth, the surface of the scintillator 3 provided on the one surface 2a of the base material 2 can be smoothed, and the optical image after conversion by the scintillator 3 can be made smooth. Resolution can be improved. As described above, according to the scintillator plate 1 according to this embodiment, the quality of images can be improved.

FIG. 7 is a diagram showing an X-ray image when using the scintillator plate 1 according to this embodiment. Comparing the X-ray image according to the above-described comparative example (see FIG. 5) with the X-ray image according to the present embodiment (see FIG. 7), it can be confirmed that the image quality is improved.

Note that, for example, it is possible to apply the scintillator 3 to a roughened surface, but in this case, as shown in FIG. 6, polishing marks (diagonal lines shown in FIG. 6) will appear in the acquired image. , the image quality deteriorates. In this manner, in terms of improving image quality, it is preferable that the scintillator 3 be applied to the mirror-finished surface 2a.

In the scintillator plate 1 described above, the surface roughness Ra of one surface 2a of the base material 2 may be 0.1 or less. Thereby, the one surface 2a of the base material 2 can be appropriately smoothed, and the quality of the image can be improved.

In the scintillator plate 1 described above, the thickness of the scintillator 3 may be 20 μm or less. For example, when acquiring an image using X-rays of low energy (for example, 30 KeV or less), the image can be appropriately acquired by reducing the thickness of the scintillator 3 to about 20 μm or less. When the thickness of the scintillator 3 becomes thinner, the surface of the scintillator 3 becomes more susceptible to the unevenness of the surface 2a of the base material 2, but as described above, the surface 2a of the base material 2 is mirror-finished. By doing so, even when the scintillator 3 is thin, image quality can be ensured.

In the scintillator plate 1 described above, the scintillator 3 may be formed of a powdered scintillator. Thereby, the scintillator 3 can be appropriately provided even when the thickness of the scintillator 3 is to be reduced, for example.

In the scintillator plate 1 described above, the base material 2 may include beryllium. By containing beryllium in the base material 2, the scintillator 3 can be held while suitably transmitting X-rays.

The X-ray image acquisition device 10 according to the present embodiment includes the scintillator plate 1 described above, a camera 50 optically coupled to the surface side of the scintillator plate 1 on which the scintillator 3 is provided, and a scintillator plate 1 that generates a scintillator. A reflecting mirror 20 that reflects light toward the camera 50 is provided. According to the X-ray image acquisition device having the scintillator plate 1 described above, the quality of captured images can be improved.

The method for manufacturing the scintillator plate 1 according to the present embodiment includes a step of mirror-finishing one surface 2a of the base material 2 that transmits X-rays (see FIG. 2(b)), and a step of mirror-finishing the surface 2a of the base material 2 after the mirror-finishing step. A step of providing a scintillator 3 on one surface 2a (see FIG. 2(c)). According to such a manufacturing method, it is possible to manufacture the scintillator plate 1 in which the scintillator 3 is appropriately provided on the mirror-finished surface (one surface 2a) of the base material 2. That is, the scintillator plate 1 that can improve the quality of images can be appropriately manufactured.

In the above-described manufacturing method, in the mirror finishing step, mirror finishing may be performed so that the surface roughness of one surface 2a of the base material 2 is 0.1 or less. Thereby, the one surface 2a of the base material 2 can be appropriately smoothed, and the quality of the image can be improved.

In the manufacturing method described above, in the step of providing the scintillator, the scintillator 3 may be provided so that the thickness of the scintillator 3 is 20 μm or less. For example, when acquiring an image using X-rays of low energy (for example, 30 KeV or less), the image can be appropriately acquired by reducing the thickness of the scintillator 3 to about 20 μm or less. When the thickness of the scintillator 3 becomes thinner, the surface of the scintillator 3 becomes more susceptible to the unevenness of the surface 2a of the base material 2, but as described above, the surface 2a of the base material 2 is mirror-finished. By doing so, even when the scintillator 3 is thin, image quality can be ensured.

In the above manufacturing method, in the step of providing a scintillator, powdered scintillator 3 may be deposited on one surface 2a of base material 2. Thereby, the scintillator 3 can be appropriately provided even when the thickness of the scintillator 3 is to be reduced, for example.

DESCRIPTION OF SYMBOLS 1...Scintillator plate, 2...Base material, 2a...One side, 3...Scintillator, 10...X-ray image acquisition device (image acquisition device), 20...Reflection mirror (reflection part), 50...Camera (imaging part).

Claims (8)

a base material that transmits X-rays;
a scintillator provided on one surface of the base material,
One surface of the base material is mirror-finished by polishing ,
The scintillator has a thickness of 20 μm or less,
The scintillator is a scintillator plate formed of a powdered scintillator. The scintillator plate according to claim 1, wherein the surface roughness Ra of one side of the base material is 0.1 or less. The scintillator plate according to claim 1 or 2, wherein the base material includes beryllium. A scintillator plate according to any one of claims 1 to 3,
an imaging section optically coupled to a surface side of the scintillator plate on which the scintillator is provided;
An image acquisition device comprising: a reflection section that reflects fluorescence generated in the scintillator plate toward the imaging section. a step of polishing one side of the base material that transmits X-rays to a mirror finish;
After the step of mirror-finishing, providing a scintillator on one surface of the base material,
The scintillator has a thickness of 20 μm or less,
The method for manufacturing a scintillator plate, wherein the scintillator is formed of a powdered scintillator. 6. The manufacturing method according to claim 5, wherein in the step of mirror-finishing, mirror-finishing is performed so that the surface roughness of one surface of the base material is 0.1 or less. 7. The manufacturing method according to claim 5, wherein in the step of providing the scintillator, the scintillator is provided so that the thickness of the scintillator is 20 μm or less. 8. The manufacturing method according to claim 5, wherein in the step of providing the scintillator, the scintillator in powder form is deposited on one surface of the base material.

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